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The sound of chime bells of 2400 years ago
The sound of chime bells of 2400 years
ago Hua Jueming The discovery in 1978 of a magnificent undamaged set of chime bells more than 2000 years old created a sensation in Chinese musical circles. As their immense value severely limited direct investigation, it was decided to make replicas and use these for research purposes. This complex task was completed in 1984. An important result of the investigation was the discovery that the bells were cast not by the tire perdue method but by casting in clay moulds. In the West bell-casting was not practised until about the eighth century A.D. and the bells were circular in section: Chinese bells have an approximately ellipsoidal section. In the autumn of 1978, astonishing news camefrom Suixian that in a previously little known county in the north of Hubei Province, China, archaeologists had discovered a huge and superb group of ancient musical instruments. They included chime bells (figure l), Qings (chime stones), Ses (a kind of stringed instrument), a drum stand and a bamboo flute, all deposited in the coffin chamber of Yi Marquis of State Zeng who died in 433 B.C. All the instruments remained intact when unearthed after thousandsof years of entombment. The discovery included the most magnificent chime bells ever seen.There were eight sets, 65 bells in all (figure 2). They were hanging in three tiers in an L-shaped arrangement; the largest bell weighed 203.6 kg and the total weight of bronze used in the eight sets,including the bronze parts of the Sun and the Ju (the horizontal beam and vertical stanchion of the bell rack, amounted to 5t). The bells were of exquisite workmanship, someof the details being as fine as hair. The date of casting of the bells could be deduced from the inscription cast on the Bo Bell presentedby the king of StateChu. Every bell could produce two musical tones of big or small third intervals. The musical alphabets and temperament were indicated by 2800 Chinese characters inscribed with gold inlay. The range of the sound of the whole group of bells spanned five and a half octaves,from C2 (64.8 Hz)
to D7 (2329.1 Hz). The 12 semi-tones of and sonorous. Both Chinese and foreign the middle three octaves were complete. compositions could be played on them The high-pitch bells sounded loud and with beautiful tones in perfect harmony, clear, while the low-pitch bells were deep producing a most moving effect.
Hua Jueming Was born in 1933 and is a graduate of TsingHua University and later of the Institute for History of Natural Sciences, Academia Sinica, of which he is now Vice-Director. He has made a close study of ancient Chinese metallurgical practices and was Director of the project for reproducing the chime bells of Yi Marquis of State Zeng, discovered in 1978.
Endeavour, New S&es, Volume 17, No. 1,199X 0160432793 saoo + 0.00. 01993 Pergamon Fbss Ltd. tinted in Great Britain.
32
Figure
1
Original
excavation
of the chime
bells
of Yi Marquis
of Zeng.
TABLE 1 SECTION NAMES OF THE YONG BELL
Gu
&
Xuan
&
Hen
4k.J
Yong
%
Sui
j$.-
Zheng
SE
wu Figure 2
The chime bells of Yi Marquis
Zhuan
%-
of State Zeng.
It was really beyond expectation that as far back as the early Warring States period (475-221 B.C.) there could appear such a magnificent group of chime bells of such high quality in respect of acoustics, materials and metallurgical technologies. Their existence established that the scale of seven tones had been used before the Qin Dynasty, and thus a long-disputed question among scholars was resolved. This important discovery caused a great sensation in academic circles. Professor Lu Ji, chairman of the Chinese Musical Association, pointed out that in view of this discovery the history of Chinese music must be rewritten. Professor McClain, of the City University of New York, praised them as the ‘eighth wonder of the world’. Found together with the bells were two heavy wooden beetles and two lighter wooden mallets for striking them (figure 3). Attempts to strike the bells with the mallet were immediately discouraged by the famous archaeologist Professor Xia Nai in order to prevent damage. To preserve and study this valuable treasure, engineer Guan Hongye and the author suggested that the whole set of bells be reproduced. Under the leadership of the Chinese State Cultural Relics Bureau, a research group composed of about 100 scientists and research specialists and technicians was immediately set up.
Figure 3 A picture of bell beating painted on a lacquer box shaped like a mandarin duck, also excavated from the tomb of Yi Marquis.
e
Reproducing the chimes Studies showed that the chimes spanned about 700 years, from the small bell (called Ling in Chinese) of the early Shang Dynasty to the Nao and Chime Nao of the late Shang Dynasty and from the Yong bell of the early Zhou Dynasty (about eleventh century to 771 B.C.) to the groups of chime bells and chime Bo (figure 4) of the Warring States period. Unlike the round cross-section of ancient European bronze bells, the cross-section of China’s ancient chime bells consisted of two near semi-circles, each of which was a little smaller than half a circle; this is the ‘composite tile form’ described by Shen Kuo, a scientist of the Song Dynasty (960 to 1279 A.D.). Another important discovery during the research was the confirmation of the Ji section (ridge) (figure 5), which was not mentioned in any ancient records. This unique structure of the bell body ensured that the attenuation of vibration of the bell was rapid. It could thus be used as a melodious musical instrument, and the two clearly distinguishable tones (the first fundamental frequency and the second fundamental frequency) obtained. The vibration mode determined with the aid of laser holographic interference techniques revealed the mystery of the double tones. When it was struck at the right centre of the Gu position, the restraining lines were at the side Gu position, and the sound production of the second fundamental frequency was restrained: thus the front Gu sound was heard. When it was struck at the side Gu position, the sound production of the first fundamental frequency was restrained, so that the side Gu sound was heard (figure 6). A book (Kao Gong Ji) of the Warring States period recorded in detail the names and size ratios of different sections of the Yong bell (table 1). Careful inspection showed that, with very small variations, the size ratio of the chime bell of Yi Marquis of Zeng was largely in conformity with the description in Kao Gong Ji, proving that the design of chime bells in this
period had been standardised and the mode of manufacture was fairly stable. Five stages in the reproduction method Various methods of examination - including X-ray spectrometry, electronic probe and scanning electronic microscopy - revealed that the bells were cast with the aid of composite pottery moulds (figure 7). The Yong bell is an example: its shape is very complicated, and the casting technique is consummate and amazing (figure 8). The forming of the mould may have proceeded as follows: (1) A specimen bell was made according to the design concept, and then a half-ellipsoid bell-model in porcelain clay was manufactured. Lines were then drawn and inscriptions cut on the model. (2) Designs and patterns to embellish the bell body were made using sectional piece moulds or printing patterns. The patterns on the bell were divided into several sections. They are identical in design, but their length and location are rather different. All the sectional moulds were cast by a mould box, and then put on the model according to the order of the drawn lines. The positions would be changeable so as to make different pattern specimens. Such a clay mould and mould box have also been excavated at Houma, in Shanxi Province (figure 9). The manufacture of Mei sections was more complicated. The moulds were all made from Mei models and located on the bell model after being dried; some clay was put on its side, and then the Mei section mould was completed. There are two kinds of Zhuan bell patterns. One consists of six units of vertical patterns, the other of five such units, located right and left. (3) The above-mentioned sectional moulds and Gu sectional moulds were then placed on the bell-model and dried to a certain strength at normal pressure without any deformation (the duration was about five to seven days or more). Clay was then added to make the cast mould for the bell body.
33
Figure 4 Stages in the development of chime bells: (1) Ling (small bell), Early Shang Dynasty; (2) Chime Nao, late (3) Yong bell, early Western Zhou Dynasty; (4) Bo bell, late Western Zhou; (5) Niu bell, Warring States period.
Shang;
Figure 5 Cross-section of the chime bell. Note the ridges?, part of which were ground out already.
(4) Piece moulds for Wu and Yong sections were also manufactured with a mould box. The Gan mould could be reproduced from models (figure 10). Yong moulds were divided according to diagonal lines, causing a distinct casting seam therein, so that an angle of 22.5” was formed between the seam and the axis. These piece-moulds made up the casting mould for the Yong section. (5) The clay cores for the bell body and the Yong section were cast by means of a core box, forming the bell cavity. The traditional method is that the core surface is marked in a lattice pattern by drawing lines on it and then scraping it with a comb (figure 11). The closer the lines and the finer the lattices, the more accurate the shapes and sizes of the cores. The weight of metal needed for melting was equivalent to eight times that of the cut-off clay. To summarise, the cast mould for a Yong bell included two sections and four
Figure7 lnnerstructureexaminationof chime bell, using ultrasonicflawdetector.
tiers. The number of the moulds and cores was about 137. The pouring process was finished in a single operation (figure 12, Table 2). Method of casting The perfect and consummate workmanship of chime bells has long been praised. Experts on metallurgy and foundry practice and students of metallurgical history held that the casting of the chime bells must have used the lost-wax (&e-per&e) process. However, our investigations show that the instrument bells of Pre-Qin period were in fact cast with assembling pottery moulds. Where the lost-wax process was not used, the key to making instrument bells with complicated shapes, fine patterns and accurate size was the adoption of meticulous casting and assembling of moulds. This special technique appeared as TABLE 2 THE CONSTITUTION
Figure 8
Yong bell of Yi Marquis.
early as the mid-Shang Dynasty. By the time of the early Warring States period it had almost reached its full potential as represented by the Yong bells of the Yi Marquis of Zeng, reaching an astonishing level. The composition of the chime bell alloy was nearly the same as that of ‘the alloy for casting bell and cauldron’ (copper six parts and tin one part), as stated in Kao Gong Ji. They were all cast of high-tin bronze, containing about 14 per cent Sn and 2-4 per cent Pb. Simulated tests showed that the overall properties of musical bells cast of metals of this composition were the best, and it could thus be called the optimum alloy composition. The purity of the metals confirmed that the raw mate-
OF A YONG BELL’S CASTING
MOULD
Yong section’s
clay core (1)
Yong section’s casting mould (1) ’ t Yong bell’s casting mould Bell body’s casting mould (2) Figure 6 Acoustic mechanism of the chime bells: (1) Front Gu sound; (2) Side Gu sound; I striking point, - restraining line.
Hen section’s piece mould (1) Yong section’s piece mould (2) including eight facing moulds Gan’s piece mould (3) + core (3) Wu section’s piece mould (4) Piece mould for patterns on circuit (19) Mei section’s piece mould (12) Mei mould (72) Zhuan section’s piece mould (8) Gu section’s piece mould (2)
I Bell body’s clay core (1)
35
Figure 9 Model and mould excavated Yong section.
at Houma,
spring and autumn
period:
(1) bell mould;
(2) model of Gu section;
(3) mould of
Mould
Cross section Figure 10
Manufacturing
of Gan mould.
rials had been refined and that the technological control over smelting and pouring was strict. The systematic study of the original bells provided a firm scientific and technical basis for the reproduction of the chime bell. However, it proved extremely difficult to make a perfect copy of such a group of complicated and exquisite bells, while retaining the original acoustic qualities. We adopted a variety of technologies such as composite pottery moulds, traditional lost-wax methods, precision casting, ceramic moulds etc. - to explore various techniques. Eventually we succeeded (figure 13). Tuning the chimes As for the method of modulating chime bells, experiments indicated that the
36
change of frequency waF related to the amount of metal ground out, and to the position of sound modulations. Some sensitive areas or points had an effect on modulation quite different from other positions. If the positions and the way of grinding (area-line-point) were correctly chosen, the frequency of the bell would be modulated to fall within a limit of only 3 per cent, as the designer had required, or even to fully harmonise and keep the tone quality harmonious. In July 1984, the reproduction of the total 65 bells and the bell rack were all completed. The audio frequency of the chime bells reached the desired standard. They were checked by more than 40 famous scholars and recognised as a great break-through in the study of ancient chime bells since the Song Dynasty.
Figure 11 at Houma.
A used cut comb, excavated
Hen mould
rl Bell mould
Bell mould
Figure 12
Casting
mould
of the Yong bell.
Yong mould
Figure 13 Yi Marquis.
Replica of the chime bells of
Summary We have made a comprehensive investigation of the chime bells’ origination and their development. We have proved that the founding technique and acoustic characteristics as well as the frequency modulation are certainly profound, but are no mystery. To manufacture the huge and complex Chinese bell groups, the ancient Chinese craftsmen and musicians employed the technological principle which we call to ‘harness complications with simplicity and imply ingenuity in plainness’. It was a great achievement of our ancestors of the Pre-Qin period, and one which we should treasure and carry forward.
37
ago Hua Jueming The discovery in 1978 of a magnificent undamaged set of chime bells more than 2000 years old created a sensation in Chinese musical circles. As their immense value severely limited direct investigation, it was decided to make replicas and use these for research purposes. This complex task was completed in 1984. An important result of the investigation was the discovery that the bells were cast not by the tire perdue method but by casting in clay moulds. In the West bell-casting was not practised until about the eighth century A.D. and the bells were circular in section: Chinese bells have an approximately ellipsoidal section. In the autumn of 1978, astonishing news camefrom Suixian that in a previously little known county in the north of Hubei Province, China, archaeologists had discovered a huge and superb group of ancient musical instruments. They included chime bells (figure l), Qings (chime stones), Ses (a kind of stringed instrument), a drum stand and a bamboo flute, all deposited in the coffin chamber of Yi Marquis of State Zeng who died in 433 B.C. All the instruments remained intact when unearthed after thousandsof years of entombment. The discovery included the most magnificent chime bells ever seen.There were eight sets, 65 bells in all (figure 2). They were hanging in three tiers in an L-shaped arrangement; the largest bell weighed 203.6 kg and the total weight of bronze used in the eight sets,including the bronze parts of the Sun and the Ju (the horizontal beam and vertical stanchion of the bell rack, amounted to 5t). The bells were of exquisite workmanship, someof the details being as fine as hair. The date of casting of the bells could be deduced from the inscription cast on the Bo Bell presentedby the king of StateChu. Every bell could produce two musical tones of big or small third intervals. The musical alphabets and temperament were indicated by 2800 Chinese characters inscribed with gold inlay. The range of the sound of the whole group of bells spanned five and a half octaves,from C2 (64.8 Hz)
to D7 (2329.1 Hz). The 12 semi-tones of and sonorous. Both Chinese and foreign the middle three octaves were complete. compositions could be played on them The high-pitch bells sounded loud and with beautiful tones in perfect harmony, clear, while the low-pitch bells were deep producing a most moving effect.
Hua Jueming Was born in 1933 and is a graduate of TsingHua University and later of the Institute for History of Natural Sciences, Academia Sinica, of which he is now Vice-Director. He has made a close study of ancient Chinese metallurgical practices and was Director of the project for reproducing the chime bells of Yi Marquis of State Zeng, discovered in 1978.
Endeavour, New S&es, Volume 17, No. 1,199X 0160432793 saoo + 0.00. 01993 Pergamon Fbss Ltd. tinted in Great Britain.
32
Figure
1
Original
excavation
of the chime
bells
of Yi Marquis
of Zeng.
TABLE 1 SECTION NAMES OF THE YONG BELL
Gu
&
Xuan
&
Hen
4k.J
Yong
%
Sui
j$.-
Zheng
SE
wu Figure 2
The chime bells of Yi Marquis
Zhuan
%-
of State Zeng.
It was really beyond expectation that as far back as the early Warring States period (475-221 B.C.) there could appear such a magnificent group of chime bells of such high quality in respect of acoustics, materials and metallurgical technologies. Their existence established that the scale of seven tones had been used before the Qin Dynasty, and thus a long-disputed question among scholars was resolved. This important discovery caused a great sensation in academic circles. Professor Lu Ji, chairman of the Chinese Musical Association, pointed out that in view of this discovery the history of Chinese music must be rewritten. Professor McClain, of the City University of New York, praised them as the ‘eighth wonder of the world’. Found together with the bells were two heavy wooden beetles and two lighter wooden mallets for striking them (figure 3). Attempts to strike the bells with the mallet were immediately discouraged by the famous archaeologist Professor Xia Nai in order to prevent damage. To preserve and study this valuable treasure, engineer Guan Hongye and the author suggested that the whole set of bells be reproduced. Under the leadership of the Chinese State Cultural Relics Bureau, a research group composed of about 100 scientists and research specialists and technicians was immediately set up.
Figure 3 A picture of bell beating painted on a lacquer box shaped like a mandarin duck, also excavated from the tomb of Yi Marquis.
e
Reproducing the chimes Studies showed that the chimes spanned about 700 years, from the small bell (called Ling in Chinese) of the early Shang Dynasty to the Nao and Chime Nao of the late Shang Dynasty and from the Yong bell of the early Zhou Dynasty (about eleventh century to 771 B.C.) to the groups of chime bells and chime Bo (figure 4) of the Warring States period. Unlike the round cross-section of ancient European bronze bells, the cross-section of China’s ancient chime bells consisted of two near semi-circles, each of which was a little smaller than half a circle; this is the ‘composite tile form’ described by Shen Kuo, a scientist of the Song Dynasty (960 to 1279 A.D.). Another important discovery during the research was the confirmation of the Ji section (ridge) (figure 5), which was not mentioned in any ancient records. This unique structure of the bell body ensured that the attenuation of vibration of the bell was rapid. It could thus be used as a melodious musical instrument, and the two clearly distinguishable tones (the first fundamental frequency and the second fundamental frequency) obtained. The vibration mode determined with the aid of laser holographic interference techniques revealed the mystery of the double tones. When it was struck at the right centre of the Gu position, the restraining lines were at the side Gu position, and the sound production of the second fundamental frequency was restrained: thus the front Gu sound was heard. When it was struck at the side Gu position, the sound production of the first fundamental frequency was restrained, so that the side Gu sound was heard (figure 6). A book (Kao Gong Ji) of the Warring States period recorded in detail the names and size ratios of different sections of the Yong bell (table 1). Careful inspection showed that, with very small variations, the size ratio of the chime bell of Yi Marquis of Zeng was largely in conformity with the description in Kao Gong Ji, proving that the design of chime bells in this
period had been standardised and the mode of manufacture was fairly stable. Five stages in the reproduction method Various methods of examination - including X-ray spectrometry, electronic probe and scanning electronic microscopy - revealed that the bells were cast with the aid of composite pottery moulds (figure 7). The Yong bell is an example: its shape is very complicated, and the casting technique is consummate and amazing (figure 8). The forming of the mould may have proceeded as follows: (1) A specimen bell was made according to the design concept, and then a half-ellipsoid bell-model in porcelain clay was manufactured. Lines were then drawn and inscriptions cut on the model. (2) Designs and patterns to embellish the bell body were made using sectional piece moulds or printing patterns. The patterns on the bell were divided into several sections. They are identical in design, but their length and location are rather different. All the sectional moulds were cast by a mould box, and then put on the model according to the order of the drawn lines. The positions would be changeable so as to make different pattern specimens. Such a clay mould and mould box have also been excavated at Houma, in Shanxi Province (figure 9). The manufacture of Mei sections was more complicated. The moulds were all made from Mei models and located on the bell model after being dried; some clay was put on its side, and then the Mei section mould was completed. There are two kinds of Zhuan bell patterns. One consists of six units of vertical patterns, the other of five such units, located right and left. (3) The above-mentioned sectional moulds and Gu sectional moulds were then placed on the bell-model and dried to a certain strength at normal pressure without any deformation (the duration was about five to seven days or more). Clay was then added to make the cast mould for the bell body.
33
Figure 4 Stages in the development of chime bells: (1) Ling (small bell), Early Shang Dynasty; (2) Chime Nao, late (3) Yong bell, early Western Zhou Dynasty; (4) Bo bell, late Western Zhou; (5) Niu bell, Warring States period.
Shang;
Figure 5 Cross-section of the chime bell. Note the ridges?, part of which were ground out already.
(4) Piece moulds for Wu and Yong sections were also manufactured with a mould box. The Gan mould could be reproduced from models (figure 10). Yong moulds were divided according to diagonal lines, causing a distinct casting seam therein, so that an angle of 22.5” was formed between the seam and the axis. These piece-moulds made up the casting mould for the Yong section. (5) The clay cores for the bell body and the Yong section were cast by means of a core box, forming the bell cavity. The traditional method is that the core surface is marked in a lattice pattern by drawing lines on it and then scraping it with a comb (figure 11). The closer the lines and the finer the lattices, the more accurate the shapes and sizes of the cores. The weight of metal needed for melting was equivalent to eight times that of the cut-off clay. To summarise, the cast mould for a Yong bell included two sections and four
Figure7 lnnerstructureexaminationof chime bell, using ultrasonicflawdetector.
tiers. The number of the moulds and cores was about 137. The pouring process was finished in a single operation (figure 12, Table 2). Method of casting The perfect and consummate workmanship of chime bells has long been praised. Experts on metallurgy and foundry practice and students of metallurgical history held that the casting of the chime bells must have used the lost-wax (&e-per&e) process. However, our investigations show that the instrument bells of Pre-Qin period were in fact cast with assembling pottery moulds. Where the lost-wax process was not used, the key to making instrument bells with complicated shapes, fine patterns and accurate size was the adoption of meticulous casting and assembling of moulds. This special technique appeared as TABLE 2 THE CONSTITUTION
Figure 8
Yong bell of Yi Marquis.
early as the mid-Shang Dynasty. By the time of the early Warring States period it had almost reached its full potential as represented by the Yong bells of the Yi Marquis of Zeng, reaching an astonishing level. The composition of the chime bell alloy was nearly the same as that of ‘the alloy for casting bell and cauldron’ (copper six parts and tin one part), as stated in Kao Gong Ji. They were all cast of high-tin bronze, containing about 14 per cent Sn and 2-4 per cent Pb. Simulated tests showed that the overall properties of musical bells cast of metals of this composition were the best, and it could thus be called the optimum alloy composition. The purity of the metals confirmed that the raw mate-
OF A YONG BELL’S CASTING
MOULD
Yong section’s
clay core (1)
Yong section’s casting mould (1) ’ t Yong bell’s casting mould Bell body’s casting mould (2) Figure 6 Acoustic mechanism of the chime bells: (1) Front Gu sound; (2) Side Gu sound; I striking point, - restraining line.
Hen section’s piece mould (1) Yong section’s piece mould (2) including eight facing moulds Gan’s piece mould (3) + core (3) Wu section’s piece mould (4) Piece mould for patterns on circuit (19) Mei section’s piece mould (12) Mei mould (72) Zhuan section’s piece mould (8) Gu section’s piece mould (2)
I Bell body’s clay core (1)
35
Figure 9 Model and mould excavated Yong section.
at Houma,
spring and autumn
period:
(1) bell mould;
(2) model of Gu section;
(3) mould of
Mould
Cross section Figure 10
Manufacturing
of Gan mould.
rials had been refined and that the technological control over smelting and pouring was strict. The systematic study of the original bells provided a firm scientific and technical basis for the reproduction of the chime bell. However, it proved extremely difficult to make a perfect copy of such a group of complicated and exquisite bells, while retaining the original acoustic qualities. We adopted a variety of technologies such as composite pottery moulds, traditional lost-wax methods, precision casting, ceramic moulds etc. - to explore various techniques. Eventually we succeeded (figure 13). Tuning the chimes As for the method of modulating chime bells, experiments indicated that the
36
change of frequency waF related to the amount of metal ground out, and to the position of sound modulations. Some sensitive areas or points had an effect on modulation quite different from other positions. If the positions and the way of grinding (area-line-point) were correctly chosen, the frequency of the bell would be modulated to fall within a limit of only 3 per cent, as the designer had required, or even to fully harmonise and keep the tone quality harmonious. In July 1984, the reproduction of the total 65 bells and the bell rack were all completed. The audio frequency of the chime bells reached the desired standard. They were checked by more than 40 famous scholars and recognised as a great break-through in the study of ancient chime bells since the Song Dynasty.
Figure 11 at Houma.
A used cut comb, excavated
Hen mould
rl Bell mould
Bell mould
Figure 12
Casting
mould
of the Yong bell.
Yong mould
Figure 13 Yi Marquis.
Replica of the chime bells of
Summary We have made a comprehensive investigation of the chime bells’ origination and their development. We have proved that the founding technique and acoustic characteristics as well as the frequency modulation are certainly profound, but are no mystery. To manufacture the huge and complex Chinese bell groups, the ancient Chinese craftsmen and musicians employed the technological principle which we call to ‘harness complications with simplicity and imply ingenuity in plainness’. It was a great achievement of our ancestors of the Pre-Qin period, and one which we should treasure and carry forward.
37